Apparatus for vulcaniziing tires



@9 v Q, El MURPHY APPARATUS FOR VULCANIZING TIRES Filed Aug. 16, 1935 2Sheets-Sheet l fjf C. E. MURPHY APPARATUS FOR VULCANIZING TIRES v FiledAug.'

16, 1953 2 Sheets-Sheet 2 www5 www? Patented Apr. 9, 1935 PATENT ori-lcsAPPARATUS Foa vULcANIziNG armas Chalmer E. Murphy, 'Cuyahoga Falls,Ohio, arssignor to Mile-O-Tiser, Inc., Akron, Ohio, a corporation ofOhio Application August 16, 1933, Serial No. 685,489

' 6 claims. (01. 11s-1s) This invention relates to apparatus forvulcanizing rubber articles and particularly to molds for retreadingautomobile tires, the present application covering an improvement uponthe vulcanizing apparatus disclosed in my prior application,

Ser. No. 576,375 filed November 20,1931.

In general terms, the object of my invention is to provide improvedapparatus of this character in which the tire carcass to be retreadedmay be readily placed and from which itmay be expeditiously removedafter the retreading operation without damaging the tread; and which isadapted to accommodate different sizes of tire casings and to insureuniform heating of the tread por- ;'i tion of the tire during thevulcanizing operation and avoid overheating of the side-walls thereof.

Another object of my invention is to provide a full-circle mold havingone or more hinged or movable segments with power means for open-l ingand closing the segments of the mold.

A further object of my invention is to provide improved supporting meansfor the side-walls of the tire carcass, preferably in the form of ringsinterlocked with the segments of the mold anc supported thereby.

A still further object of my invention is to provide improved means forwithdrawing the retreaded tire from the mold.

A still further object of my invention is to provide a mold of thecharacter described having a detachable liner with improved means forwedging the liner into tight contact with the heating element of themold.

Other objects and advantages of my invention will appear from thefollowing detailed description of the preferred embodiment thereof shownin the accompanying drawings wherein Figure l is an elevational view ofthe mold as constructed for retreading automobile tires;

Fig. 2 is a side view of the moid shown in Fig. 1;

Fig. 3 is a sectional View taken on the line III-111 of Fig. l, showingthe tire carcass and supporting rim thereforv in` section; and

Fig. 4 is a similar View showing the adaptation of the apparatus to asmaller tire. 4

While the invention is not limited to apparatus for retreadingautomobile tires, certain features thereof are particularly useful inconnection with such apparatus or apparatus for vulcanizng articlesofsimilarshape. Consequently,r in order to explain the featuresof theinvention, I havev 5 treading apparatus shown comprises a segmental moldconsisting of a lower fixed segment l and movable segments 2 and 3hinged to the segment l at the points e and 5, respectively, in orderthat the mold may be opened or spread to permit the tire to be mountedtherein or removed there- 5 from in a semi-rigid or inated condition. Aspointed out in my prior application, above referred to, in afull-circlemold of the character described, it is essential that ,a segmental orkexpansible mold be employed for retreading tires lo since the tire maybe partially inflated orin a semi-rigid condition when it is placed inthe mold so that wrinkles and air-pockets are avoided and a balanceduniform tread is secured `as required by high driving speeds.l Also byconstructing the l5 mold in segments which are outwardly movable inopening the mold after the retreading'operation,` as indicated in dottedlines in Fig. 1, the possibility of damaging the tread in removing thetire from the mold is greatly reduced.

The segments l, 2 and 3 of the mold engage the entire tread surface ofthe tire and when the segments are closed, a true circular mold isformed as necessitated by the requirement of `-a balanced tread. Asshown, the hinges 4 and 5 25 are of substantial size and may includeroller bearings orhardened wearing surfaces so that after prolonged use,the segments will still line up perfectly and form a true circularvulcanizing Surface. While it is preferable to employ three 30 segmentsas shown, each of the movable segments extending for approximately onethird of the circumferenceof the tread, in some cases only two segmentsor more than three segments may be employed. o

One of the segments may be arranged to form a base or support for themold in any desired manner. As shown, thefixed segment i is providedwith legs t attached to the segment by pins or bolts 'i and braced bythe tie rods 6.

The hinged segments 2 and 3 are provided at their upper ends withcontiguous integral lugs lil and Il, respectively. Suitable means forlocking the mold in closed relation is provided on said lugs. As shown,the lug 'I is provided with a concave surface l2 conforming to the shapeof a cam-shaped locking member I3 provided with a projecting handle' I4.The member I3 is pivoted between the ends of two link members i5 whichare pivotally carried by the lug H on the segment 3. The describedconstruction provides a simple and effective toggle latch by which thesegments of the mold may bequickly clamped and-,locked in closedrelation against the internal pressure in the mold during thevulcanizing bodiment shown, this power means comprises a hydraulic orfluid-pressure cylinder 23 having a piston 2l therein, the' movement ofthe Vpiston being controlled in the usual manner by admitting andexhausting fluid under pressure to opposite sides of the piston byconventional control valves (not shown).

In the preferred arrangement shown, the power cylinder 23 is mountedvertically midway between the ends of the lower Vsegment `i and isbolted or otherwise secured thereto in any convenient manner. TheVreciprocable piston 2| in said cylinder is secured to a piston rod 22extending through a packing gland 23 at the upper end of the cylinder 28and a guide 24 adjacent the upper ends of the moldsegments 2 and 8. The

'guide 24 is supported by vertical brackets 25 integral with or mountedupon the cylinder 20.

Thus the piston rod 22 coincides with the radius of the mold passingthrough the contiguous ends of the movable segments v2 and 3.

,' Ihe operating means for spreading the segments of the' mold includesconnecting members keo Yin the usual manner.

secured in any desired manner to the pistcnrod 22; for example toabracket member 25 mounted thereon intermediate the ends of the rod. The

' connecting members, as shown, comprise two link members 21 pivoted attheir lower ends to the bracket member 25 and at their` upper ends tothe upper ends of the segments 2 and 3 as indicated at 28, So that theraising and lowering 0i the piston 2| and piston rod opens and closesthe vsegments of the mold. By reason o the high internal pressuresemployed during the vulcanizing operation, manual locking means asdescribed above is alsoprovided for securing the Segments of the mold inclosed relation after the mold has been closed upon the tirel to beretreadedt In order to remove the tire from the segment I of the moldafter the r'etreading operation, means may be provided for clamping thetire to one of the movable segments so that the Vtire is lifted from thexed Vsegment as the movable segments are opened or spread. As shown,such means may comprise a chain 29 which is looped around the tire andthe upper end of one of the movable segments of the mold. 1

Any suitable means may be provided for heating the segments of the moldduring the vulcanizing operation. If steam or other uid heating mediumis employed, the segments are hol-- low and are provided with inlet andoutlet openings for circulation ofthe heating medium. The temperaturemay be closelyv regulated as required by controlling the pressure of thesteam In the mold shown, inlet ports 30 and 3l are provided adjacent theupper ends of the segmentsk 2 and 3 respectively. In accordancewith afurther' feature of the invention, the segments 2 and 3 are providedwith outlet openings 32 and 33 at the extreme lower portions of saidsegments whereby'the trapping of condensate in the mold isavoided as itvis found that only in this way cany uniform heating of the mold beinsured. The segment I of the mold is similarly provided withVinlet-ports 34 and 35 at oppositejends thereof and an outlet 36 at thebottom of the mold. I f desired, the ports 32-34 and 33-35may beconnected by the usual flexible connections so that the heating mediumcirculates through the segments 2 and 3 into the fixed segment l and outthrough theV liner is provided with recesses and projections i vto`enable a tread o f theV desired character and 4appearance to be formedupon the tire. Y'I'he liner is held in position `by clamping studs orpins 42 having tapering or wedge-shaped pointsV 43 adapted to engagesuitable recesses or parts of the liner and thereby force` the linerinto snug contact with the cooperating heating portion of the mold. y

VIn order to'support the lside-walls of the tire during the .retreadingvoperation, supporting members G5, preferably ring-shaped, are provided.-The supporting members45 are not divided in segments as in the caseiofthe mold but are circumferentially continuous and, when thesesments ofthe mold areclosed, are'interlooled with the mold or the liner thereofso as to be firmly braced against the pressure exerted by the tire. AsshownV in` Fig.v 3, ythe supporting member 45 and the liner may beprovided with cooperating grooves and Vprojections, for this purpose.When the mold-is-opened, the V supporte ing members 45 may be readilylifted out of the mold to facilitate the removal of the tire from the'mold It will be noted that since the mold only vheating `of thesidewalls `of the tire is avoided.

Such overheating of the sidewalls of the tire would .cause deteriorationof the fabric as, well understood by those skilled in the art,

Referring to Fig. 3, in retreading a tire, after the usual builingoperation, thek tire with the cement and tread stock 5I thereon isinserted in the mold. VThe tire may be mounted upon a supporting rim` 52of a diameter depending upon the size of the tire.V In order that thetire may be partially inflated before closing the mold, an inner tube 53is used, the valve stem of the inner rtuoe being indicated at 54. Therim 52 is pro.- vided with a slot 55 to receive the valve stem 5ft.Byepartially inflating the tire before .the mold is jclosed, wrinkles inthe tread surface and air pockets between the tire and mold are avoided.The provisiono power means for closing the mold permits ready closure ofthe mold against a semi-rigid tire carcass. be further inflated, ifdesired, after closure of the mold until the necessary vulcanizingpressure is obtained. mold to cure the tread in thevusual manner.

As shown in Fig. 4, if the diameter of the rim 56 upon which the tirerismounted is greater than ing between said members. When the mold isclosed and the tirer5 is fully inflated, the beadsv of the tire aresupported partly by the rim 56 and partly by the-members 45, asindicated ,in dotted The tire may.`

Then steam is admitted to the` 52 (Figs. 3 and 4) and thus obviate thenecessity of employing a supporting rim similar to an ordinary wheel rimprovided with means to prevent the beads vfrom spreading under theinternal pressure.

Various modications of the construction shown and described will occurtothose skilled in the art, and such modifications are considered withinthe scope of the invention if within the scope of the appended claims.

I claim:

l. A vulcanizer of the character described comprising an annular elementformed of a lower fixed segment and a pair of movable segments pivotallyconnected at one end to the adjacent ends of said fixed segment, saidsegments being of substantially equal circumferential lengths andprovided with independent heating chambers the inner peripheral surfaceof said segments being recessed, sectional cooperating matrices ofcomplementary lengths removably disposed in the recessed portions ofsaid segments and movable with the movable segments, said matriceshaving tread forming portions on the inner peripheral surface thereof,and removable and replaceable continuous circular side wall engagingmembers disposed upon opposite sides and forming annular inwardlyextending Ycontinuations of said matrices, there being interengagingformations between the adjacent ends of said matrices and said membersto thereby secure said members against relative movement when saidsegments' lengths and provided with independent heatingchambers, theinner peripheral surface of said segments being recessed, sectionalcooperating matrices of complementary lengths removably disposed in therecessed portions of said segments and movable with the movablesegments, said matrices having tread forming portions on the innerperipheral surface thereof, means detachably mounted on the side wallsof said segments and operatively connected to said sectional matricesfor retaining the latter in proper position in said recesses, andremovable and replaceable continuous circular side wall engaging membersdisposed upon opposite sides and forming annular inwardly extendingcontinuations of said matrices, there being interengaging formationsbetween the adjacent ends of said matrices and said members to therebysecure said members against relative movement when said segments are inclosed position.

3. A vulcanizer of the character described comprising an annular elementformed of a lower xed segment and a pair of movable segments pivotallyconnected at one end to the adjacent ends of said xed segment, saidsegments being of substantially equal circumferential lengths andprovided with independent heating chambers, the inner peripheral surfaceof said segments being recessed, sectional cooperating matrices ofcomplementary lengths removably disposed in the recessed portions ofsaid segments and movable with the movable segments, said matriceshaving tread forming portions on the inner peripheral surface thereof,bolts detachably mounted on the side walls of said segments and havingreduced inner ends cooperating with aligned openings provided in theadjacent sides of' said sectional thel `ends of said xed segment, saidsegments being of substantially equal circumferential lengths andprovided with independent heating chambers, the inner peripheral surfaceof said segments being recessed, sectional cooperating matrices ofcomplementary lengths removablydisposed in the recessed portions of saidsegments and movable with the movable segments, said matrices havingtread forming portions on the inner peripheral surface thereof, andremovable and replaceable continuous circular side wall members disposedupon opposite sides and forming annular inwardly extending continuationsof said matrices, there being interengaging formations between theadjacent ends of said matrices and said members to thereby secure saidmembers against relative movement when said segments are in closedposition, said members being of less thickness than the adjacent.portions of said matrices.

5. A vulcanizer of the character described comprising an annular elementformed of a lower xed segment and a pair of movable segments pivotallyconnected at one end to the adjacent ends of said fixed segment, saidsegments being of substantially equal circumferential lengths andprovided with independent heating chambers, the inner peripheral surfaceof said segments being recessed, sectional cooperating matrices ofcomplementary lengths removably disposed in the recessed portions ofsaid segments and movable with the movable segments, said matriceshaving lbeing interengaging formations between the adjacent ends of saidmatrices and said members to thereby secure said members againstrelative movement when said segments are in closed position, saidmembers being of less thickness than the adjacent portions of saidmatrices and having tapered outer annular surfaces extending inwardly.

6. A vulcanizer of the character described comprising an annular elementformed of a lower iixed segment and a pair of movable segments pivotallyconnected at one end tothe adjacent ends of said fixed segment, saidsegments being of substantially equal Vcircumferential lengths andprovided with independent heating chambers, the inner peripheral surfaceof said segments being recessed, sectional cooperating matrices ofcomplementary lengths removably disposed in the recessed portions ofsaid segments and movable with the movable segments, said matriceshaving tread forming portions on the inner peripheral surface thereof,means 'detachably mounted on the side walls of said segments andoperatively connected to said sectional matrices for retaining thelatter in proper position in said recesses,V and removable andreplaceable Continuous circular side Wall engaging members disposed uponopposite sides and forming annular inwardly extending continuations ofsaid matrices, there being interengagng formations be-Y tween theadjacent ends of said matrices and said members to thereby secure saidlmembers` matrieesrand having tapered outer annular Suri faces extendinginwardly. i l Y CHALMER E. MURPHY.

